Modern science shows that the principles recorded in Donguibogam are far from outdated concepts. When the biological rhythm—the delicate 24-hour balance between the nervous system and hormones—breaks down, it leads to insomnia and compromises deep sleep. At the center of this process is the relationship between the sleep hormone melatonin and the stress hormone cortisol.
At night, relying on light exposure and activity patterns accumulated during the day, the body signals that it is time for rest. The pineal gland in the brain then begins secreting melatonin. Melatonin gently lowers body temperature, steadies the heart rate, and calms brain activity to encourage natural sleep. However, exposure to smartphone screens before bed, late-night high-intensity exercise, or excessive stress suppresses melatonin secretion, leading the brain to assume it is still daytime.
Cortisol balance is equally important. Cortisol peaks in the morning to promote wakefulness and daily activity, but chronic stress and irregular routines keep levels elevated at night. This keeps the body tense and alert during the very hours intended for rest. Donguibogam's observation that the spirit cannot settle aligns closely with this modern understanding of nervous system hyperactivation and hormonal imbalance.
Over time, poor sleep quality produces consequences that reach well beyond everyday tiredness. During sleep, the brain clears metabolic waste built up during the day, consolidates memories, and restores energy for the hours ahead. Without adequate deep sleep, immunity weakens, blood glucose regulation falters, and the risk of cardiovascular disease rises. In the case of snoring, it is not merely an annoying sound; it can signal sleep apnea, where the airway narrows and restricts breathing. Prolonged breathing pauses during the night deprive the brain and heart of sufficient oxygen, leading to daytime sleepiness, impaired concentration, hypertension, and arrhythmia. Just as Donguibogam emphasized the proper circulation of qi and blood, modern medicine stresses that balanced energy flow and coordinated organ function are fundamental to restful sleep. Resetting your biological rhythm is the true starting point for restoring lasting health.
